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Home >> Suzuki >> 2001 >> Vitara JS, 4D Utility, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0420: Catalyst System Low Efficiency >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Perform DTC CONFIRMATION TEST . If DTC P0420 is set, go to next step. If DTC P0420 is not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
  2. Inspect exhaust system for damage or leaks and repair as necessary. If no problems were found with exhaust system, go to next step.
  3. Turn ignition off. Connect scan tool. Drive vehicle for at least 2 minutes at 35 MPH or greater. While revving engine, observe HO2S No. 2 parameter on scan tool display. If scan tool displays continuously varying voltage above and below .3 volts, replace catalyst and go to DTC CONFIRMATION TEST . If voltage is not as specified, check for short or open in Red/Green wire between HO2S No. 2 and PCM 35-pin connector E61 terminal No. 26. See WIRING DIAGRAMS article. If wire is okay, check for short or open in Gray/Yellow wire between HO2S No. 2 and PCM 35-pin connector E61 terminal No. 24. Repair as necessary. If wire is okay, go to next step.
  4. Disconnect HO2S No. 2 connector and PCM 35-pin connector E61. Check for poor terminal contact at HO2S No. 2 connector and PCM 35-pin connector E61. If poor terminal contact is found, repair as necessary and go to DTC CONFIRMATION TEST . If terminal contact is okay, replace HO2S No. 2 and go to DTC CONFIRMATION TEST .
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